Again, I test the 4.16 kernel with the parameter "nomodese". As Kaihengfeng guessed the system boot but the problem still there; /sys/class/backlight folder was empty. My second test was boot again with 4.16 without "nomodeset" parameter in the grub file and the results were others. As I expected the system was frozen and in this last test the brightness keys didn't work. It smells like a problem betwen my firmware and the kernel. I can do more test to find the problem.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1758496 Title: Backlight does not work on a MacBookAir3,2 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1758496/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs